HBO seems to have gotten hacked earlier this Monday, and it seems like some written material from the next episode may have been leaked online.

Hackers claimed to have obtained 1.5 terabytes of data from the company. So far, an upcoming episode of Ballers and Room 104 have apparently been put online. There is also written material that’s allegedly from next week’s fourth episode of Game of Thrones. More is promised to be “coming soon.” HBO is not commenting on what content might have been stolen, confirming specific titles or the amount of data accessed. This morning, HBO chairman and CEO Richard Plepler sent an email to HBO employees alerting them of the breach.

It’s not clear if the hackers actually have what would be the crown jewel target for an HBO cyber breach — upcoming episodes of the company’s biggest hit, Game of Thrones. So far, no GoT episodes have leaked.

For years, HBO has fought a cyber-battle to keep Game of Thrones storylines secret and the show’s content from being illegally distributed — particularly before episodes air. In season 5, the first four episodes leaked online before the show’s season premiere after review DVDs that were sent to the press and industry insiders. HBO has since halted the practice of sending any episodes in advance. That same year, some clips leaked ahead of time from overseas HBO distributors, and even images of Jon Snow’s death found their way online before the finale aired. Just a couple weeks ago, a Thrones trailer to be screened at Comic-Con leaked onto YouTube in advance of its release. But those incidents were accidental content leaks. This is the first time the company has been the victim of an actual cyber attack.